In the calculation of the addition, subtraction, multiplication and division equation, if you carelessly write some numbers or symbols in the equation incorrectly, it will lead to an error in the calculation result, and if you want the correct answer, you must reasonably calculate the known conditions in the problem.
1. Add number + add number = sum
(1) One additive number becomes larger, the other addition number does not change, and becomes larger;
(1) One additive number becomes smaller, the other adds the same number, and becomes smaller.
2, the number of subtractions - subtraction = difference
(1) The subtracted number becomes smaller, the subtraction does not change, and the difference becomes smaller;
(2) The subtracted number becomes larger, the subtraction does not change, and the difference becomes larger;
(3) The subtraction is unchanged, the subtraction becomes larger, and the difference becomes smaller;
(4) The subtracted number does not change, the subtraction becomes smaller, and the difference becomes larger
3. Division without remainder: divisor÷ divisor = quotient
4. Look at the wrong remainder, first find out the divisor, and then find the correct quotient;
5, there is a division of the remainder: look at the wrong divisor, the remainder is the same, want to calculate how much the difference between the two divisors, and then use the difference number divided by the quotient, first find out the divisor.
The following exercises parents can do for their children from the first grade,
Do it for your child according to your child's actual level.
For example, the second grade can do the first grade problem, the third grade can do the second grade problem, and so on.
Reference Answer:
1、50+（40-4）=86
2、28+（66-6）=88
3、15+（27-24）=18
4、18+（42-24）=36
5、88-（66-6）=28
6、66-（33-3）=36
7、18-（42-24）=0
8、15-(65-56)=9
9、66-(66-6)=6
10、45+(88-68)=65
1、70-54+45=63
2、66-34+43=75
3、96-（69-15）=42
4、7+61-16=52
5、88+（8-3）-（50-20）=63
6、99-（6-3）-（70-20）=46
7、18+（80-30）+（50-20）=98
8、8-（7-5）+（70-10）=66
1、（158-126）÷2= 16
2、55×6÷9=36…… 6
3、128×6÷4=192
4、123×8÷6=164
5、129×5÷3=215
6、（131-113）÷3=6
7、(173-137)÷4=9 137÷9=15…… 2
8、（174-147）÷3=9 174÷9=19…… 3
9、 126×5+3=633 633÷3=211
1, one plus increases by 10, assuming that the other plus number is unchanged, and the sum increases by 10; suppose one plus is unchanged, the other plus decreases by 15, and decreases by 15; and first increases 10, then decreases 15, so the sum decreases by 5.
2、533+（500-3）=1030。
3、100-65=35。
4、（1305-5）÷52=25 1350÷25=54。
5、9-6=3 936-864=72 72÷3=24 864÷24=36
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